Progress in medical research worldwide is dependent on the safe, rapid, reliable and convenient exchange of biological specimens that are optimally preserved. Without the confidence that cryopreserved specimens being shipped among clinical sites, research laboratories and/or repositories will retain their integrity for the intended purposes - whether for in-vitro viability or functionality assays, or for in-vivo clinical or research purposes, the biomedical and biotechnological advances are seriously jeopardized. To date, the three-decade old safety innovation of the non-spill ("dry") vapor-phase liquid nitrogen (LN2, at-126 C, 77K) shipping tank, has only been applied to one commercial shipper possessing both a capacity for (up to 4) standard size freezer storage boxes and able to meet the IATA regulations for shipping cryopreserved infectious substances. A larger (6-12 freezer box) capacity, certified for both thousands of cryovialed specimens (biomedical research) and for infectious tissues or organs (disease control investigations; biodefense responses) can provide great flexibility while complying fully with IATA and US DOT regulations The earlier Phase I (see Introduction) simply showed that it was possible to use solid foams highly adsorbent of LN2 for greatly improved spill-proofing; and light-weight polymers having high strength at LN2 temperatures to replace aluminum for the body of the Dewar vessel. This current program will develop new data to optimize these components and to prove the feasibility of an innovative, low-cost; LN2 vapor-phase cooled Frozen Specimen Shipping Unit. Key innovations include: (1) proprietary no-spill, faster-adsorbing material for the LN2 reservoir; (2) a lightweight polymer matedal (plastic) for the vessel ("Dewar") instead of aluminum; and (3) novel aerospace-type cryogenic insulation to extend holding time. Crucial to this Phase 1 program is optimizing a polymer for low temperature material strength and high vacuum service. In Summary, Phase I specific aims are: 1.Develop analytic techniques to compare polymers for Dewar vessel matedal to achieve high vacuum. 2. Select polymer and barrier techniques for enhanced cryogenic insulation. 3. Specify cryogenic insulation based on comparative properties (incl: holding time, cost, structural contribution to two-point suspension, degradation of performance with time).